What is erosion?
Erosion is the process by which rock and soil are worn away and moved by water, wind, ice or gravity. Over time, it shapes landscapes such as canyons, valleys and coastlines.
Erosion often follows weathering, the breaking down of rock into smaller pieces. Rivers carry sediment downstream, cutting deeper channels over thousands of years. Waves pound coastlines, creating cliffs, caves and arches. Glaciers scrape and carry huge amounts of rock as they move, and wind blows sand across deserts.
Gravity causes erosion too, through landslides and rockfalls. The eroded material, called sediment, is eventually deposited somewhere else, building up deltas, beaches and sand dunes. The Grand Canyon is a famous example of erosion by the Colorado River over millions of years.
Soil erosion
Human activities, such as cutting down forests, overgrazing and plowing, can speed up soil erosion. Losing fertile topsoil makes farming harder and can cause rivers to fill with mud. Planting trees, using terraces and keeping plants growing on fields help protect soil.
Did You Know?
The Dust Bowl of the 1930s in the US Great Plains was caused by drought combined with soil erosion from poor farming practices, creating huge dust storms.